The wrapper project
Thu Aug 21 15:24:24 CEST 2003
On Thu, 21 Aug 2003, Joachim Durchholz wrote:
> Joe Armstrong wrote:
> > 2) The components must communicate by asynchronous message passing
> I have an exception to consider:
> When composing subcomponents from components,
Uugh - do you mean the other way around?
You make components from sub-components ... ????
> *and* a crashing subcomponent shall crash the entire component,
> *then* synchronous communication is appropriate.
I assume you meant that
1) components are made from sub-components
2) if a sub-component crashes you want the component to crash
To do this (if that's what you meant) I would like asynchronous messages.
The problem with synchronous messages is that you can't implement
them. The laws of physics preclude this. You need to send a message
between the systems (which even at the speed of light takes finite
time) to send information between the systems - you also change the
> At least if that "synchronous communication" is a simple subroutine call
> - emulating synchronous messages on top of an asynchronous layer like
> Erlang's messages and pipes isn't doing much good.
But I wouldn't emulate synchronous messages on top of the messages
and pipes I'd use discrete events or RPC's with timeouts. I would also
make no assumptions about the cause of the absence of a message.
> Just my 2c.
> Flame me as appropriate :-)
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